U.S. patent number 5,549,600 [Application Number 08/270,032] was granted by the patent office on 1996-08-27 for surgical laser probe with thermal cutting.
This patent grant is currently assigned to Cynosure, Inc.. Invention is credited to George Cho.
United States Patent |
5,549,600 |
Cho |
August 27, 1996 |
Surgical laser probe with thermal cutting
Abstract
In an apparatus and method for thermal cutting with a surgical
laser probe, fiber optics convey laser light from a source to the
surgery region. The laser beam is directed towards tissue for
vaporizing the tissue. A bulbous tip member is coupled to the
output end of the fiber optics. Vaporization of the tissue by the
laser generates charred tissue particulates which naturally collect
on the face of the bulbous tip member. The collected charred tissue
absorbs reflected light energy from the laser vaporization of
tissue. The absorbed energy heats the tip member which causes
vaporization of proximate tissue.
Inventors: |
Cho; George (Hopkinton,
MA) |
Assignee: |
Cynosure, Inc. (Bedford,
MA)
|
Family
ID: |
23029603 |
Appl.
No.: |
08/270,032 |
Filed: |
July 1, 1994 |
Current U.S.
Class: |
606/15; 606/16;
606/28; 606/7 |
Current CPC
Class: |
A61B
18/24 (20130101); A61B 18/28 (20130101) |
Current International
Class: |
A61B
18/20 (20060101); A61B 18/28 (20060101); A61B
18/24 (20060101); A61B 017/36 () |
Field of
Search: |
;606/27,28,2,3,7,13-16 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Sykes; Angela D.
Assistant Examiner: Peffley; Michael
Attorney, Agent or Firm: Hamilton, Brook, Smith, &
Reynolds, P.C.
Claims
What is claimed is:
1. A surgical laser probe comprising:
fiber optics having an input end and an output end for conveying
light;
a laser light source optically coupled to the input end of the
fiber optics for providing a laser beam conveyed by the fiber
optics of sufficient intensity to vaporize and cause charring of
tissue in the laser beam path; and
a bulbous, hollow tip member of refractory material, transparent to
light at the laser source wavelength, coupled to the output end of
the fiber optics, the laser beam being directed toward tissue for
vaporizing the tissue with light energy, causing charring of the
tissue, the tip member providing a surface surrounding the output
end of the fiber optics whereon the vaporized charred tissue
collects, the charred tissue absorbing light energy reflected from
the tissue causing heating on the tip member for vaporizing the
tissue proximate to the tip member with thermal energy, the laser
beam being of sufficient intensity to maintain continued
vaporization of tissue with light energy as charred tissue collects
on the surface of the tip member.
2. The surgical laser probe of claim 1, wherein the tip includes a
hole for retaining the output end of the fiber optics.
3. The surgical laser probe of claim 2, wherein the diameter of the
fiber optics is substantially similar to the diameter of the hole,
providing a snug fit for retaining the fiber optics in the tip.
4. The surgical laser probe of claim 2, wherein the output end of
the fiber optics is fused to the hole for retaining the fiber
optics in the tip.
5. The surgical laser probe of claim 2 wherein the hole is formed
in an extension adapted to retain the fiber optics in the hole in a
recessed position so that contact between the output end of the
fiber optics and tissue is avoided.
6. The surgical laser probe of claim 1, wherein the tip is
substantially solid having a hole along its length for retaining
the output end of the fiber optics.
7. The surgical laser probe of claim 6, wherein the diameter of the
fiber optics is substantially similar to the diameter of the hole,
providing a snug fit for retaining the fiber optics in the tip.
8. The surgical laser probe of claim 6, wherein the output end of
the fiber optics is fused to the hole for retaining the fiber
optics in the tip.
9. The surgical laser probe of claim 1 wherein the tip comprises
silica.
10. The surgical laser probe of claim 1 wherein the surface of the
tip member is less than approximately four millimeters from the
output end of the fiber optics.
11. A method of performing surgery comprising:
coupling a laser light source to fiber optics, the fiber optics
having an input end and an output end;
coupling a bulboust, hollow tip member of refractory material
transparent to light at the laser source wavelength to the output
end of the fiber optics;
conveying a laser beam from the laser light source through the
fiber optics and tip, the laser beam being of sufficient intensity
to vaporize and cause charring of tissue in the laser beam
path;
directing the laser beam towards tissue for vaporizing the tissue
with light energy, causing charring of the tissue; and
collecting vaporized charred tissue on a surface of the tip member,
the charred tissue absorbing light energy reflected from the
tissue, causing heating on the tip member for vaporizing the tissue
proximate to the tip member with thermal energy, the laser beam
being of sufficient intensity to maintain continued vaporization of
tissue with light energy from the laser beam as charred tissue
collects on the surface of the tip member.
12. The method claim 11 further comprising the step of providing a
hole on the tip for retaining the output end of the fiber
optics.
13. The method of claim 12 further comprising the step of coupling
the fiber optics to the tip with a snug fit between the output end
of the fiber optics and the hole.
14. The method of claim 12 further comprising the step of fusing
the output end of the fiber optics to the hole for retaining the
fiber optics within the tip.
15. The method of claim 12 further comprising the step of forming
the hole in an extension adapted to retain the fiber optics in the
hole in a recessed position such that contact between the output
end of the fiber optics and tissue is avoided.
16. The method of claim 11 further comprising the step of forming a
substantially solid tip having a hole along its length for
retaining the output end of the fiber optics.
17. The method of claim 16, further comprising the step of coupling
the fiber optics to the tip with a snug fit between the output end
of the fiber optics and the hole.
18. The method of claim 16 further comprising the step of fusing
the output end of the fiber optics to the hole, for retaining the
fiber optics in the tip.
19. The method of claim 11 further comprising the step of forming
the tip member from silica.
20. The method of claim 11 further comprising the step of disposing
the output end of the fiber optics within four millimeters from the
surface of the tip member.
Description
BACKGROUND OF THE INVENTION
Endoscopic surgery is often used to perform prostate,
intra-uterine, bladder, and urinary tract surgery. The most common
method of performing prostate surgery is to resect the enlarged
prostate gland with an electrosurgical loop inserted into the
urethra through an endoscope. The electrosurgical device shaves off
small pieces of prostate tissue in order to enlarge the passageway
thereby providing the patient with relief. A problem with this
method of surgery is that substantial bleeding occurs as the
prostate tissue is cut, making visibility through the endoscope
difficult. Blood loss also complicates the surgical operation and
lengthens the hospital stay. This method of surgery is lengthy and
difficult to perform and requires extensive training.
In another method, fiber optics are inserted into the prostate
gland through an endoscope. Divergent laser energy conveyed by the
optical fiber coagulates surrounding prostate gland tissue. The
coagulated tissue remains in place for about 4 to 6 weeks before
passing during urination. Therefore, the patient must endure a long
period of discomfort and may need a catheter to assist urine
passage until the coagulated tissue passes.
Another method employs thermal cauterization using a probe with a
hot metal tip. Fiber optics are inserted into the prostate gland
through an endoscope. Laser energy is supplied for heating a metal
tip located on the end of the fiber optics. Tissue within proximity
to the metal tip is cauterized. A disadvantage of this method is
its inaccuracy.
SUMMARY OF THE INVENTION
The present invention relates to an apparatus and method for
thermal cutting with a surgical laser probe. The apparatus of the
invention includes fiber optics, a laser light source, and a
bulbous tip member. The laser light source is optically coupled to
the input end of the fiber optics. The fiber optics convey laser
light from the light source to the output end of the fiber optics.
The laser beam is directed towards tissue for vaporizing the
tissue. The bulbous tip member is coupled to the output end of the
fiber optics. Charred tissue vaporized by the laser beam collects
on the tip member, which absorbs heat energy from reflected laser
light, causing the tip member to heat up. Heat radiated by the tip
member vaporizes tissue proximate to the tip member.
The bulbous tip may be continuous across its face or may have a
hole for communicating with the fiber optics. The bulbous tip may
include an extension on its face for communicating with fiber
optics. In the case where the tip is continuous across its face, it
is preferred that the bulbous tip comprise material which is
transparent to light at the laser wavelength. The face of the
bulbous tip may include a hole for communicating with the fiber
optics. The diameter of the fiber optics may be substantially
similar to the diameter of the hole providing a snug fit for
securing the fiber optics in the hole. The fiber optics may be
secured in the hole by fusing the fiber optics to the bulbous tip.
The bulbous tip may be substantially solid having a hole along its
length for communicating with the fiber optics.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features and advantages of the
invention will be apparent from the following more particular
description of preferred embodiments of the invention, as
illustrated in the accompanying drawings in which like reference
characters refer to the same parts throughout the different views.
The drawings are not necessarily to scale, emphasis instead being
placed upon illustrating the principles of the invention.
FIG. 1 is a sectional side illustration of a surgical laser probe
used for prostate surgery in accordance with the present
invention.
FIG. 2 is a close-up sectional side view of a light delivery tip
vaporizing tissue thermally and with laser light in accordance with
the present invention.
FIG. 3 is a sectional side view of a light delivery tip having a
hole and an extension in its front face for communicating with the
fiber optics in accordance with the present invention.
FIG. 4 is a sectional side view of a light delivery tip having a
continuous front face in accordance with the present invention.
FIG. 5 is a sectional side view of a light delivery tip wherein the
fiber optics is fused at its output end in accordance with the
present invention.
FIG. 6 is a sectional side view of a light delivery tip wherein the
fiber optics is fused at its output end and the tip is solid in
accordance with the present invention.
FIG. 7 is an endoscopic view of a prostate with tissue excised.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 is a sectional side illustration of a surgical laser probe
with thermal cutting used for performing prostate surgery. The
probe includes a laser light source 12 coupled to the input end of
fiber optics 16 at connector 13. Connector 13 is of the low profile
type described in U.S. patent application Ser. No. 08/242,308
incorporated herein by reference. The fiber optics 16 pass through
an endoscopic sheath 22. The endoscopic sheath 22 includes viewing
optics (not shown) for enabling a surgeon to view surgical areas. A
light delivery tip 28 is coupled to the output end of the fiber
optics 16. The surgeon, using the viewing optics, guides the light
delivery tip 28 into regions of the prostate 26 to be excised.
FIG. 2 is a close-up sectional side view of a light delivery tip 28
excising tissue 70 from the prostate. The surgeon guides the light
delivery tip 28 into a region of the prostate where tissue 70 is to
be excised. Upon positioning the light delivery tip 28, which
includes a bulbous tip member 48, the surgeon projects a beam of
laser light through the fiber optics 40 which radiates 14 at the
tissue vaporization site 62. The tissue 70 is vaporized into
charred particulates 64 which by natural process collect 66 on the
front face 43 of the bulbous tip member 48. The charred
particulates 64 are residual carbon from tissue following removal
of H.sub.2 0 and C0.sub.2 through vaporization. The collection of
charred tissue 66 is black in color and therefore absorbs heat
energy from reflected laser light 68. The bulbous tip member 48 is
hottest at its front face 43, where most laser energy is absorbed
and coolest at its rear face 41. The heating of the bulbous tip
member 48 causes further vaporization of tissue 72 in regions
adjacent the bulbous tip member 48. Therefore, tissue 70 is
vaporized both by the laser beam energy 14 and by the thermal
energy absorbed by the charred particulates 66 and radiated by the
bulbous tip member 48.
The output end of the fiber optics 40 is preferably within
approximately 4 mm of the front face 43 of the tip 48, for
providing high power density laser energy 14 at the tissue
vaporization site 62. The laser beam 14 gives quick, efficient
vaporization of tissue while permitting the surgeon to direct the
fiber optics 40 closer to the tissue. In this way, the power
density is high in the region of vaporization, and is low in nearby
regions.
FIGS. 3-6 are sectional side views of various embodiments of light
delivery tips in accordance with the present invention. In each
embodiment, the fiber optics 40 includes a reflective cladding
layer (not shown) for directing the beam longitudinally and for
reducing leakage. The fiber optics 40 also includes a buffer sleeve
42 for protecting the fiber optics 40 from breakage and scratching.
The buffer sleeve 42 is stripped at the output end of the fiber
optics 40. A bulbous tip member 46, 48, 52, 56 is fitted over the
exposed area of the fiber optics 40 and secured to the fiber optics
40 with epoxy 44. By coupling the fiber optics 40 to the inside of
the bulbous tip 46, 48, 52, 56, a strong bond is given. An intense,
highly concentrated beam of laser light 14 is emitted from the
output end of the fiber optics 40.
In FIG. 3 the bulbous tip 46 has an extension 47 on its front face.
The front face of the bulbous tip 46 includes a hole 45 for
allowing laser light 14 to pass therethrough. The hole 45 is
substantially similar in diameter to the outer diameter of the
fiber optics 40 and thus, the fiber optics 40 fits snugly in the
hole 45 and communicates with the extension 47. The snug fit
secures the bulbous tip 46 in place. The extension 47 simplifies
the process of aligning the fiber optics 40 within the bulbous tip.
The fiber optics 40 is recessed slightly within the hole 45 so that
contact with tissue is avoided. The recession of the fiber optics
40 within the hole 45 is slight, so as not to cause substantial
divergence of the laser beam 14. The snug fit also protects the
cladding of the exposed fiber within the bulbous tip 46 from damage
which would cause further beam divergence. Any leakage of energy
from the fiber optics 40 within the bulbous tip 46 gets absorbed by
the charred tissue, heating the bulbous tip.
In FIG. 4 the bulbous tip 48 is continuous on its face and is
transparent to light at the laser source wavelength. The output end
of the fiber optics 40 is butt-coupled 49 to the inner wall 51 of
the front face of the bulbous tip 48. In an embodiment wherein the
fiber optics 40 is not butt-coupled 49 to the inner wall 51, the
output end of the fiber optics 40 is preferably within 4
millimeters of the front face of the bulbous tip 48, permitting
close, efficient vaporization of tissue.
In FIG. 5, the bulbous tip 52 is similar in shape to the bulbous
tip 48 of FIG. 4. However, the tip 52 of FIG. 5 includes a hole 53
on its front face. The hole 53 allows the fiber optics 40 to pass
therethrough. The output end of the fiber optics 40 is fused 54,
coupling 61 the fiber optics 40 to the bulbous tip 52 around the
perimeter of the fiber optics 40, protecting the exposed region of
the fiber optics within the cavity of the bulbous tip from charred
particulates and from reflected laser energy. Prior art included a
ball fused to the end of fiber optics for diverging the laser beam.
However, in such embodiments, initiation was slow and mere
coagulation resulted rather than cutting or vaporization of the
tissue. The present invention immediately vaporizes the tissue with
a high power density beam and is much quicker in cutting larger
areas with the heating action of the bulb.
In FIG. 6, the bulbous tip 56 is substantially solid in comparison
to the embodiments of FIGS. 3, 4 and 5. The bulbous tip 56 includes
a hole 55, allowing the fiber optics 40 to be seated therein. The
output end of the fiber optics 40 is positioned to align with the
front face of the bulbous tip 56 and is fused 57. The fusion
couples 59 the fiber optics 40 to the bulbous tip 56 around the
perimeter of the fiber optics 40. Alternatively, the fiber optics
40 may be secured in the hole 55 with a snug fit, similar to the
embodiment of FIG. 3. In this embodiment, the diameter of the hole
56 is substantially similar to the diameter of the fiber optics 55.
The snug fit secures the fiber optics in the hole without the need
for fusion.
In the embodiments of FIG. 5 and FIG. 6, the cladding proximate to
the output end of the fiber optics is preferably removed before
fusing the fiber optics 40 to the bulbous tip 52. The cladding
layer commonly comprises a plastic material which cannot withstand
the preferred 1,000.degree. C. fusion temperature of the silica
fiber optics and silica bulb.
FIG. 7 is an endoscopic view of a prostate after completion of
surgery. Tissue 26 is systematically vaporized along the length of
the prostate, widening the prostate canal. Crescent shaped regions
60 remain in the tissue 26 where tissue has been vaporized.
A typical prostate urethra has a diameter on the order of 4-6 mm
when not dilated. A preferred diameter for the fiber optics is
approximately 0.5 to 1.0 mm while a preferred outer diameter of a
bulbous tip at its widest point is approximately 5.0 mm.
The term "fiber optics" as used herein includes a single fiber or a
bundle of fibers. Typically, a single optical fiber has a diameter
ranging between 0.5 and 1.5 mm. Preferred fiber optics comprise
quartz fibers having thin reflective cladding layers, which promote
longitudinal propagation of laser light.
The bulbous light delivery tip preferably comprises silica. Other
heat absorbing materials, for example metal, may be used. The
bulbous tip preferably comprises a refractory material such that it
withstands high temperatures. The material is preferably capable of
withstanding a range of temperatures from 100.degree. C., the
vaporization temperature of tissue, up to 800.degree. C. for
absorbing laser radiation.
The thickness of the bulbous tip is not easily controllable, and
preferably ranges from 0.05 mm to 0.5 mm for the hollow bulbs of
FIG. 4 and FIG. 5. The front face of the tip may be thicker than
the body of the tip as shown in FIG. 4, up to 2 mm which may create
a lens effect.
The laser source preferably comprises a laser from the following
group: Nd:YAG (1.06 .mu.m and 1.44 .mu.m); Ho:YAG (2.10 .mu.m);
Tm:YAG (1.94 .mu.m); and diode lasers (800 nm-1 .mu.m). The source
is preferably capable of providing power output ranging from 10 W
to 100 W in continuous wave or pulsed operation.
The described application of the present invention in endoscopic
prostate surgery is intended as an illustration and is not intended
as a limitation. The present invention is useful in many other
applications where extraction of tissue is required, endoscopic or
otherwise.
While this invention has been particularly shown and described with
references to preferred embodiments thereof, it will be understood
by those skilled in the art that various changes in form and
details may be made therein without departing from the spirit and
scope of the invention as defined by the appended claims.
* * * * *